Manufacture of pigmented viscose rayon



United States atent O 3,033,697 MANUFACTURE OF PIGMENTED VISCOSE RAYONBrewster B. Eskridge, Candler, N.C., assignor to American EnkaCorporation, Enka, N.C., a corporation of Delaware No Drawing. Filed May31, 1960, Ser. No. 32,593 9 Claims. (Cl. 106166) This invention relatesgenerally to the manufacture of pigmented viscose rayon articles such asfilaments, threads, fibers, and the like and more particularly to themanufacture of solution-colored and/or delustered viscose rayonarticles.

In the prior art, various methods have been proposed for the productionof pigmented viscose rayon. If a solution-colored yarn is desired, ithas been customary to incorporate one or more organic coloring pigmentsinto the viscose spinning solution. One ditficulty in such a method wasthat the fabrics obtained from such yarn exhibited dichroism. It wasproposed in US. Patent No. 2,934,449 that the above could be overcome bythe incorporation into the viscose spinning solution of a small amountof a substantially white inorganic delustering pigment.

If a delustered yarn is desired, it has been proposed that a relativelylarge amount, for example 1.0% to 5.0%, based on the weight of thecellulose in the viscose, be incorporated into the viscose spinningsolution. Thus it was possible to obtain a dull luster yarn or adelustered and solution colored yarn which depends upon the absence orpresence of organic coloring pigments in the viscose solution.

Many difiiculties have arisen in the use of the finely divideddelustering pigments either alone or in conjunction with organiccoloring pigments. They exhibit a strong tendency to settle out of theviscose solution. Also, they may agglomerate and clog the spinningorifices or cause weak spots in the yarn, thereby reducing the qualityof the yarn. It has been proposed that dispersing agents be used toovercome these problems. However, difiiculties have arisen here becausethey may be precipitated out of the viscose spinning solution by themetal cations present therein, or they may not be compatible with theorganic coloring pigments or their dispersing agents. They may also beprecipitated by the organic coloring pigments or their dispersingagents.

It is therefore an object of the present invention to provide a processfor the production of pigmented viscose rayon that is free of thedifficulties of the prior art.

It is a further object of the present invention to provide a viscosespinning solution for the manufacture of solution-colored viscose rayon.

A further object of this invention is to provide a viscose spinningsolution for the manufacture of solutioncolored rayon wherein settlingout of the pigments is substantially eliminated.

Another object of the present invention is to provide a viscose spinningsolution for the manufacture of solution-colored rayon whereinprecipitation of the dispersing agent used therein does not occur.

An additional object of this invention is to provide a viscose spinningsolution for the manufacture of delustered and/ or solution-coloredrayon wherein the pigments retain their finely dispersed state.

These and other objects of this invention are accomplished by providinga viscose spinning solution having dispersed therein an organic coloringpigment and/or a substantially white inorganic delustering pigment, aprimary aliphatic amine containing 12 to 18 carbon atoms, and sodiumN-coco 'beta-aminopropionate or disodium N-tallowbeta-iminodipropionate. These propionates "ice are known in the trade asDeriphats and are N-substituted amino acid derivatives (beta-alanines).They are derived from the condensation of fatty primary amines andacrylic monomers. Coco denotes a mixture of fatty acids obtained fromcoconut oil, and tallow indicates a mixture of fatty acids obtained fromtallow fat. These mixed fatty acids have straight carbon radicalsranging from about 8 to 24 carbon atoms with the individual amines in adistribution corresponding to the distribution of the fatty acids of theparticular fat or oil.

By the introduction of the amine and propionate into the viscosespinning solution by way of the pigment dispersion, it was unexpectedlyfound that it was possible to produce a delustered and/orsolution-colored viscose rayon yarn in which the pigments were finelydispersed. In addition, there was no evidence of a precipitate whichcould be attributed to the pigments or compounds. Also, there was asubstantial reduction in the settling out of the delustering pigment.

The substantially white inorganic pigments that are contemplated by thisinvention are those commonly known as delustrants. Examples of these aretitanium dioxide, tin oxide, barium sulfate, lead sulfate, and zincoxide. The preferred compound is titanium dioxide. If dichroism is to beprevented in a lustrous solution-colored yarn, then it is only necessarythat about 0.01-0.10%, based on the weight of the cellulose in theviscose (hereinafter referred as CIV) be dispersed in the viscosesolution. However, if a delustered yarn is desired, then about 1.0 to5.0% CIV should be used, and if a delustered and solution-colored yarnis desired, then normally about 0.1 to 1.0% CIV will be used. It shouldbe understood that this invention is not restricted to any precise rangesince it is obvious that the proportions of the delustrant may varywithin wide limits, depending on the pigment and the type of coloringmaterial used.

The coloring materials contemplated by this invention are conventionalorganic coloring pigments. Examples of these are Microsol Yellow,Imperse Red, Stabaloid Black, Monolite Yellow. Monolite Red, AquablackX, and Monastral Green. The amount of the coloring pigment will varydepending upon the desired color. The selection of the pigments andtheir amounts are easily determined by means known to those skilled inthe art.

The aliphatic amines required for successful operation of this inventionare those that contain 12 to 18 carbon atoms, as for example, laurylamine and oleyl amine. It is only necessary that very small amounts ofthe amine be incorporated into the viscose spinning solution. Forinstance, if 0.01 to 0.1% (CIV) titanium dioxide is used, normally0.0005 to 0.005% (CIV) will be sufficient. However, if 1.0 to 5.0% (CIV)of titanium dioxide is to be used, then normally 0.05 to 0.25% (CIV)will be sufiicient to aid in the prevention of settling out of thepigments and precipitation of any of the salts present therein. Itshould be understood that larger or smaller amounts may be used withoutdeparting from this invention.

The second organic compound contemplated by this invention for use inconjunction with the above pigments is sodium N-cocobeta-aminopropionate or disodium N- tallow beta-iminodipropionate. It isonly necessary that very small amounts of these compounds be used. Forinstance, if 0.01 to 0.1% (CIV) titanium dioxide is used, normally0.0006 to 0.006% (CIV) will be suflicient. However, if 1.0 to 5.0% (CIV)titanium dioxide is to be used, then normally 0.06 to 30% (CIV) will besulficient to aid in the prevention of settling out of the pigments andprecipitation of any of the salts present therein. It should beunderstood that larger or smaller amounts may be used withoutappreciably affecting the results.

The dispersion of these pigments and organic compounds in the viscosesolution may be accomplished in any conventional manner. For instance, astable slurry of the inorganic pigment and two organic compounds isprepared by uniformly dispersing the same in a liquid, for example,water. The pigment slurry may be prepared by grinding the inorganicpigment and two organic compounds in the presence of water in a pebblemill, a ball mill, a colloid mill such as a Charlotte mill, or a homomixer. The resulting dispersion does not exhibit any settling out forseveral days.

If a delustered viscose rayon yarn is desired, an appropriate aliquotmay be withdrawn from this slurry and incorporated into the viscosespinning solution. Normally the same will be injected into a flowingstream of viscose and thereafter the viscose and pigment dispersion arepassed through a conventional mixing stage wherein the same arethoroughly mixed throughout the viscose spinning solution. Thereafterthe pigmented viscose solution is extruded into a conventionalcoagulating bath to form filaments therefrom.

An organic coloring pigment may be separately incorporated into theviscose solution before or after the above pigment dispersion. It mayalso be incorporated into the pigment dispersion and thereafter injectedor otherwise incorporated into the viscose spinning solution. The amountof organic pigments used will, of course depend upon the color and shadedesired. In addition, the amount of inorganic pigment used will dependupon whether only dichroism is to be prevented or that a delustered andsolution-colored yarn is to be obtained.

It should be understood that any conventional makeup of the pigments andorganic compounds may be used. In addition, any method of dispersing thesame in the viscose spinning solution may be used without departing fromthis invention.

The following examples are included merely for the purpose ofillustration and are not to be considered as limiting the scope of thisinvention.

Example I An aqueous dispersion of 20% titanium dioxide, 1.0% primarylauryl amine, and 1.25% disodium N-tallow beta-iminodipropionate wasprepared by mixing the same in a homo mixer. A predetermined portion ofthe dispersion was withdrawn and was added to a viscose solutionprepared in the usual manner. The formulation was 1.0% (CIV) titaniumdioxide, 0.05% (CIV) primary lauryl amine, and 0.06% (CIV) disodiumN-tallow beta-iminodipropionate. The delustered viscose was extrudedthrough a spinneret into an acid coagulating bath. The finishedfilaments were closely wound on a viewing card and exhibited a dullluster.

The pigment dispersion did not settle on standing, and the titaniumdioxide was thoroughly dispersed in the resulting yarn. The spinnabilityof this viscose was normal, and the quality was normal.

Example II An aqueous dispersion of titanium dioxide was prepared as inExample I. A predetermined portion of this dispersion was withdrawn andwas added to a coloring pigment suspension. After thorough mixing, apredetermined amount of the resulting dispersion was added to a viscosesolution prepared in the usual manner. The formulation was 0.7% (CIV)Monolite Yellow, 0.725%. (CIV) Monolite Red, 0.35% (CIV) Aquablack X,0.45% (CIV) titanium dioxide, 0.0225 (CIV) primary lauryl amine, and0.027% (CIV) disodium N-tallow beta-iminodipr'pionate, Thesolntion-colored viscose was extruded through a spinner'et into an acidcoagulating bath. The finished filaments so produced were closely woundon a viewing card. When the filaments were viewed at different angles,there was no detectably different surface color perceptions and thecolor was autumn brown.

The pigment dispersion did not settle on standing and there was noprecipitate formed. In addition, the yarn was uniformly colored and thepigments were thoroughly dispersed throughout the yarn. The spinnabilityof the viscose and the quality of the yarn were normal.

Example III An aqueous dispersion of 20% titanium dioxide, 1.0% primarylauryl amine, and 1.25% disodium N-tallow beta-iminodipropionate wasprepared by mixing the same in a homo mixer. The dispersion was allowedto stand for seven days, and there was no settling of the titaniumdioxide which remained thoroughly dispersed therein.

A portion of this dispersion was added to several standard organiccoloring suspensions and there was no settling or precipitation evident.

Example IV An aqueous dispersion was prepared as in Example III exceptsodium N-coco beta-arninopropionate was substituted for the disodiumcompound. This dispersion was allowed to stand for seven days and theresult was the same as in Example III. Also there was no settling orprecipitation when a portion of this dispersion was added to standardorganic coloring suspensions.

Example V An aqueous dispersion was prepared in the same manner as inExample III, except primary oleyl amine was substituted for the laurylamine. This dispersion did not settle after seven days nor did itexhibit any precipitation when mixed with standard organic coloringsuspensions.

It can be seen from the foregoing examples that delustering pigmentdispersions and/ or solution-coloring dispersions may be prepared, whichdispersions do not settle on long standing, nor is any precipitateformed. This permits the yarn producer to prepare large amounts of thepigment dispersions which may be stored for several days. This resultsin substantial economy in his operations. In addition, the same do notlower the spinnability of the viscose or the quality of the yarn, and atthe same time produce a uniformly delustered and/or solutioncoloredviscose rayon yarn.

It should be understood that various modifications may be made in thisinvention without departing from its spirit and scope, which is to belimited only by the following claims.

What is claimed is:

1. A viscose spinning solution for the manufacture of rayon filamentshaving dispersed therein 0.01 to 5.0% (CIV) of a finely dividedsubstantially white inorganic delustering pigment, 0.0005 to 0.25% (CIV)of a primary aliphatic amine containing 12 to 18 carbon atoms, and0.0006 to 0.3% (CIV) of a compound selected from the group consisting ofdisodium N-tallow beta-iminodi propionate and sodium N-cocobeta-aminopropionate.

2. A viscose spinning solution according to claim 1 wherein saidinorganic pigment is titanium dioxide.

3. A viscose spinning solution according to claim 1 wherein saidcompound is disodium N-tallow beta-iminodipropionate.

4. A viscose spinning solution according to claim 1 wherein saidcompound is sodium N-coco beta-aminopropionate.

5. A viscose spinning solution according to claim 1 wherein the primaryaliphatic amine is lauryl amine.

6. A viscose spinning solution according to claim 1 wherein the primaryaliphatic amine is oleyl amine.

7. A viscose spinning solution for the manufacture of rayon filamentshaving dispersed therein an organic color ing pigment, 0.01 to 5.0%(CIV) of a finely divided substantially white inorganic delusteringpigment, 0.0005 to 0.25 (CIV) of a primary aliphatic amine containing 12to 18 carbon atoms, and 0.0006 to 0.3% (CIV) of a compound selected fromthe group consisting of disodium N-tallow beta-iminodipropionate andsodium N-coco betaaminopropionate.

8. A viscose spinning solution for the manufacture of delustered rayonfilaments having dispersed therein 1.0 to 5.0% (CIV) titanium dioxide,0.05 to 0.25% (CIV) of a primary aliphatic amine containing 12 to 18carbon atoms, and 0.06 to 0.3% (CIV) of a compound selected from thegroup consisting of disodium N-tallow betaiminodipropionate and sodiumN-coco beta-aminopropionate.

9. A viscose spinning solution for the manufacture of solution-coloredrayon filaments having dispersed therein an organic coloring pigment,0.01 to 1.0% (CIV) titanium References Cited in the file of this patentUNITED STATES PATENTS 2,481,692 Schlosser et a1 Sept. 13, 1949 2,867,540Harris Jan. 6, 1959 2,927,091 Liggett Mar. 1, 1960 2,934,449 Jones Apr.26, 1960

1. A VISCOSE SPINNING SOLUTION FOR THE MANUFACTURE OF RAYON FILAMENTSHAVING DISPERSED THEREIN 0.01 TO 5.0% (CIV) OF A FINELY DIVIDEDSUBSTANTIALLY WHITE INORGANIC DELUSTERING PIGMENT, 0.0005 TO 0.25% (CIV)OF A PRIMARY ALIPHATIC AMINE CONTAINING 12 TO 18 CARBON ATOMS AND 0.0006TO 0.3% (CIV) OF A COMPOUND SELECTED FROM THE GROUP CONSISTING OFDISODIUM N-TALLOW BETA-IMINODIPROPIONATE AND SOLIDIUM N-COCOBETA-AMINOPROPIONATE.